Oil burner



June 7, 1938.

J. B. HARRINGTON OIL BURNER Original Filed Dec. 2, 1935 i; ATTORNEY.

Patented June 7, 1938 UNITED STATES PATENT OFFICE OIL BURNER James B. Harrington, Dorchcster, Boston, Mass., assignor to The Waverly Heating Supply 00., Boston, Mass., a corporation of Massachusetts 6 Claims.

This invention relates to oil burners of the type designed more especially for use in domestic ranges and similar heating apparatus. It aims to improve oil burners of this character with a view especially to facilitating the starting of such burners and reducing the length of time required to bring them up to a normal operating condition.

The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawing, and the novel features will be particularly pointed out in the appended claims.

In the drawing,

Figure l is a plan view of a burner base embodying features of this invention;

Fig. 2 is a vertical, sectional view substantially on the line 2-2, Fig, 1, and illustrating, also, the perforated sleeves which are supported on the base; and

Fig. 3 is a fragmentary, sectional View on approximately the line 33, Fig. 1.

The burner base shown in the drawing is most conveniently made by casting, although it can be manufactured in other ways, and it includes inner and outer grooves 2 and 3, respectively, for conducting oil and combustible vapors. Extending upwardly from the inner groove are two perforated metal sleeves 4 and 5, respectively, which cooperate with the groove to provide an inner combustion chamber, and similar sleeves 6 and 1 are associated with the outer groove 3 to provide an outer combustion chamber. Preferably the base, the grooves, and the sleeves are of circular form, as in the common commercial constructions. The oil is fed initially to one of the grooves and is conducted to the other through radial ducts 8, Figs. 1 and 3, cored in the base and serving to connect the two grooves together at intervals. Usually, also, wicks, such as those shown at 9 and In, Fig. 3, are located in the respective grooves 2 and 3. Air openings l2 are provided through the base and open into the space between the two combustion chambers.

So far as the features above described are concerned, the construction is essentially like that of the common commercial oil burners of this general character. In starting up such a burner it is the usual practice to allow oil to flow into the grooves in the burner base until it at least fills them up to a point considerably above the lower edges of the wicks, and then to light the wicks at several places by means of a lighted taper. The flame soon spreads, and after the burner has been in operation for several minutes the sleeves become heated and transmit their heat to the metal base, thus serving to vaporize the oil in the grooves more rapidly. As the parts heat up, the vaporizing action becomes more rapid until finally a normal rate of vaporization of the oil is produced, and the flames in the two concentric combustion chambers are fed almost completely, if not entirely, by vapor so generated, very little liquid oil being present in the burner base. When the burner first starts the flame is of a yellowish, smoky character, but it becomes cleaner as the burner heats up, and finally takes on the clear bluish color which is characteristic of normal operation. Usually, however, considerable time elapses, in the neighborhood of twenty minutes, between the initial lighting of the burner and the establishing of normal operation. To reduce this period of time constitutes the chief object of this invention.

In the construction shown the inner groove 2 is made of triangular form in vertical section, the inner wall of this groove consisting of an inclined annular member M of the burner base. Oil is conducted into the inner margin of this groove through the hole l5, an oil supply pipe (not shown) being threaded into the boss is through which this hole is formed. From this inlet the oil flows around the entire inner surface of the groove 2 and through the radial passages a into the outer groove 3. One of the perforated sleeves for the inner combustion chamber, in this particular arrangement the inner sleeve 4, instead of being mounted in the usual manner, is extended down almost to the bottom of the oil groove 2 so that its lower margin projects into the body of.oil present in this groove during the starting period. Qil passages are formed under the edge of this sleeve by providing a series of radial lugs I! extending from the outer wall of the groove 2 part way across said groove, the lower edge of the sleeve 4 resting on'the upper surfaces of these lugs.

In starting this burner into operation the usual practice above described may be followed, The

fact, however, that the sleeve 4 extends down-- After the wicks have been lighted, or the burner has been started in anyother way, the sleeves are the first parts to receive heat, and the inner sleeve 4 heats up more rapidly than any of the others. .In the arrangement shown, this inner sleeve transmits its heat 'very rapidly, both by conduction and also by radiation, to the incoming oil. It is important, in order to produce the best results, that the thermal conductivity between the inner sleeve 4 and the base shall be poor, to the end that an eflicient conduction of heat be maintained from the upper part of the sleeve to its lower margin. Thus the lower part of this sleeve, resting in the oil groove, will be kept at as high a temperature as possible, and its effectiveness in vaporizing the oil will be correspondingly increased. For this purpose the area of contact between the sleeve and the base is reduced to a minimum. Such contact consists simply of that between the lower edge of the sleeve and the lugs I1 and a very small contact of the inner surface of the sleeve with the rounded outer margin of the inner wall l4 of the base. The base usually is cast while the sleeve is of sheet metal and, due to the eccentricities of these two elements, they do not fit tightly together but practically always are in touch at only three or four points around the edge of the wall l 4. Also, as the sleeve heats up and expands, the area of contact tendsto become smaller. In any event, the entire surface contact is such that very little heat is transmitted from the sleeve to the upper part of the base. At its extreme lower edge the loss of heat also is small, but it is not so important here as it would be at points above for the reason that the high temperature is utilized in the region where the sleeve is immersed in the oil during the starting operation. It is in this region that it is important to have a high temperature maintained. Careful tests have shown that the construction illustrated produces these results. Upon starting the burner, the sleeve 4 heats up very much more rapidly than the base and within a very few minutes the lower margin of the sleeve which is submerged in oil attains a temperature of several hundred degrees higher than adjacent portions of the base. This materially reduces the time required to bring the burner up to its normal operating condition. Also this temperature difference is maintained continuously.

In addition to the foregoing, the sloping inner wall M of the burner base is rapidly heated by the radiant heat transmitted from the inner surfaces of the cylindrical sleeve 4, and assists in heating the oil in the inner groove.

After the burner has been in operation for a few minutes, it is usually customary to partially open the oil feed valve so that a continuous flow of oil comes in through the inlet l5 and into the inner margin of the groove 2 where it flows around the entire circumference of this groove, and thence outward radially into the outer part of the groove 2 and through the passages 8 into the outer groove 3. Thus the part of the groove 2 inside of the sleeve 4 may be considered as an oil distributing and vaporizing groove, and that outside of the sleeve 4 as part of the combustion chamber, or, as the oil groove for the inner combustion chamber, these two groove sections being separated by the lower margin of the inner sleeve 4. As the incoming oil flows through the oil distributing section of the inner groove, it is vaporized by the heat of the base, and more especially by the higher temperature of the lower margin of the inner sleeve, and this vapor is distributed to the grooves at the bases of the combustion chambers between the inner and outer pairs of perforated sleeves. Experience has shown that the construction provided by this invention produces a better operating condition and a higher ultimate temperature when the innermost sleeve 4 is extended down into the inner oil groove, as above described. This appears to be due to the more rapid vaporization produced by the lower margin of the sleeve even after the burner base has become thoroughly heated up. The best explanation that I can give for this result is that the highly heated lower margin of the sleeve, projecting into the space where vaporization is taking place, maintains a higher temperature in this vaporizing zone than otherwise would be possible. Also, as the vapor is generated and flows: upwardly along the inner surface of the wall l4, it is guided by this wall through the perforations in the sleeve 4 where its temperature is increased even further.

This application is a continuation of my copending application Serial No. 700,698, filed December 2, 1933.

While I have herein shown and described, a preferred embodiment of my invention, it will be understod-that the invention may-be embodied in other forms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

1. In an oil burner, the combination with a burner base having an oil groove therein, of a pair of perforated sleeves extending upwardly from said groove and spaced apart, said sleeves cooperating with said groove to provide a combustion chamber, the inner of said sleeves extending downwardly approximately to the bottom of said groove but the area of contact of said sleeve with said base being so restricted that the rate of transfer of heat from the sleeve to the base is abnormally low and the temperature of the portion of said sleeve in said groove is maintained high, and means for conducting oil into said groove.

2. In an oil burner, the combination with a burner base having a circular oil groove therein, of a pair of perforated sleeves supported on said base and extending'upwardly from said groove, said, sleeves being spaced apart and cooperating with said groove to provide a combustion chamber, the inner of said sleeves extending downwardly into the space in said groove occupied by the oil during the starting of the burner and dividing said groove into an inner oil vaporizing and distributing section and a combustion section, said sleeve and said base being constructed and-arranged to facilitate the efficient transmission of heat from the upper portion of the sleeve into the lower margin thereof so that said lower margin will be maintained at a considerably higher temperature than the base and will thereby serve to vaporize the oil in said groove during the starting of the burner, and means for conducting oil into said inner section of said groove.

3. In an oil burner, the combination of a burnerbase having a circular oil groove therein the inner wall of which is inclined upwardly and outwardly, a pair of spaced perforated sleeves extending upwardly from the side walls of said groove, said sleeves cooperating with said groove to provide a combustion chamber, the inner of said sleeves extending downwardly into said groove and dividing said groove into an inner fuel vaporizing and distributing chamber and an outer combustion compartment, and means supporting said inner sleeve slightly above the bottom ofsaid groove whereby the lower end of said sleeve is immersed'in liquid fuelduring the starting period to conduct heat thereto to aid rapid vaporization, and means for conducting oil into said inner chamber, the outer inclined surface of said inner wall being exposed to the radiant heat from the inner sleeve of the burner.

4. In an oil burner, the combination of a burner base having two circular concentric grooves therein, the inner wall of the inner of said grooves being inclined upwardly and outwardly, two pairs of perforated sleeves extending upwardly from the respective grooves, each pair cooperating with its respective groove to provide a combustion chamber, the innermost of said sleeves extending downwardly into the space in the inner groove occupied by the oil during the starting of the burner and dividing said inner groove into inner and outer sections, means for conducting oil into said inner section of the latter groove, said base having passages connecting said grooves through which the fuel can flow freely from the inner to the outer groove, said base and said innermost sleeve being constructed and arranged to support the sleeve in its operative position while protecting said sleeve from any substantial heat conducting contact with said base at points above its lower edge.

5. In an oil burner, the combination with a burner base having an oil groove therein, of a pair of perforated sleeves extending upwardly from said groove and spaced apart, said sleeves cooperating with said groove to provide a combustion chamber, the inner of said sleeves extending downwardly approximately to the bottom of said groove, to present a substantial heat conducting area to oil therein, said inner sleeve and said base having edge to surface contact only, with each other, whereby the area of contact therebetween is so restricted and in such poor heat conducting relationship that the rate of transfer of heat from the sleeve to the base is abnormally low and the temperature of the portion of the sleeve in said groove below the initial oil level therein is maintained high, and means for conducting oil into said groove.

6. In an oil burner, the combination with a burner base having an oil groove therein and means for conducting oil into said groove, of a pair of perforated sleeves extending upwardly from said groove and spaced apart, said sleeves cooperating with said groove to provide a combustion chamber, and means to transmit the high temperature of the upper portion of the inner of said sleeves to the lower margin thereof to produce and facilitate a rapid vaporization of said oil including an extension of said inner sleeve downwardly into the space in said groove occupied by the oil during the starting of the burner to a point substantially below the initial oil level in the groove, and a mounting for said sleeve with its extended portion, constructed and arranged to provide a poor heat conducting relationship to said base whereby to minimize dissipation of heat directly to said base.

JAMES B. HARRINGTON. 

